# ComMysqlJdbcExceptionsJdbc4::CommunicationsException: Communications link failure, if i schedule query every system hour

**URL:** <https://discuss.elastic.co/t/commysqljdbcexceptionsjdbc4-communications-link-failure-if-i-schedule-query-every-system-hour/170330>\
**Category:** Logstash\
**Created:** [February 28, 2019, 11:40am UTC](https://discuss.elastic.co/t/commysqljdbcexceptionsjdbc4-communications-link-failure-if-i-schedule-query-every-system-hour/170330 "2019-02-28T11:40:11Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![ApekshaB](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/apekshab/32/63273_2.png) [@ApekshaB](https://discuss.elastic.co/u/ApekshaB)\
**Post date:** [February 28, 2019, 11:40am UTC](https://discuss.elastic.co/t/commysqljdbcexceptionsjdbc4-communications-link-failure-if-i-schedule-query-every-system-hour/170330/1 "2019-02-28T11:40:11Z")

</div>

Kindly find my conf file as below:

input {  
jdbc {  
jdbc\_connection\_string =\> "jdbc:mysql://172.23.125.52:3304/faredge"

```
    jdbc_user => "faredge"
    jdbc_password => "faredge"
	jdbc_driver_library => "D:\Apeksha\ELK_6.4_Series\logstash-5.4.0\mysql-connector-java-5.1.47\mysql-connector-java-5.1.47-bin.jar"
    jdbc_driver_class => "Java::com.mysql.jdbc.Driver"
	statement => "select id, txn_type, request_time from faredge.txn_data_table WHERE request_time > CURRENT_DATE - interval '8' day"

	use_column_value => true
	tracking_column => "request_time"
	tracking_column_type => "timestamp"
	
	jdbc_paging_enabled => "true"
	jdbc_page_size => "50000"
	jdbc_default_timezone => "Asia/Kolkata"
	last_run_metadata_path => "C:\Users\apeksha.bhandari\.logstash_payse_sql_001"
	schedule => "0 */1 * * *"

}

```

}  
filter {  
mutate {  
convert =\> {  
"mobile\_no" =\> "string"  
}  
}  
}

output {  
stdout { codec =\> json }

```
	elasticsearch {
	hosts => ["10.1.54.76:9200"]
	index => "thurs_28_002"		
	document_id => "%{id}" 
	retry_on_conflict => 3	
	}
file {
            codec => json_lines
            path => "D:\Apeksha\logstash-5.4.0\thurs_28_002.log"
    }

```

}

* * *

If i run scheduler every 5min, i am not facing any issue, but if i use scheduler to run query every system hour, i get below error:

The last packet successfully received from the server was 1,424,940 milliseconds ago. The last packet sent successfully to the server was 30 milliseconds ago.: SELECT count(\*) AS `count` FROM (select id, txn\_type, request\_time from faredge.txn\_data\_table WHERE request\_time \> CURRENT\_DATE - interval '8' day) AS `t1` LIMIT 1  
17:00:00.188 [Ruby-0-Thread-18: D:/Apeksha/logstash-5.4.0/vendor/bundle/jruby/1.9/gems/rufus-scheduler-3.0.9/lib/rufus/scheduler/jobs.rb:283] WARN logstash.inputs.jdbc - Exception when executing JDBC query {:exception=\>#\<Sequel::DatabaseDisconnectError: Java::ComMysqlJdbcExceptionsJdbc4::CommunicationsException: Communications link failure

The last packet successfully received from the server was 1,424,940 milliseconds ago. The last packet sent successfully to the server was 30 milliseconds ago.\>}

Kindly help.

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<div class="post-metadata">

**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [February 28, 2019, 2:17pm UTC](https://discuss.elastic.co/t/commysqljdbcexceptionsjdbc4-communications-link-failure-if-i-schedule-query-every-system-hour/170330/2 "2019-02-28T14:17:45Z")

</div>

It sounds like the remote server is timing out the connection. Does setting the jdbc\_validate\_connection option to true help?

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<div class="post-metadata">

**Author:** ![ApekshaB](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/apekshab/32/63273_2.png) [@ApekshaB](https://discuss.elastic.co/u/ApekshaB)\
**Post date:** [March 1, 2019, 7:23am UTC](https://discuss.elastic.co/t/commysqljdbcexceptionsjdbc4-communications-link-failure-if-i-schedule-query-every-system-hour/170330/3 "2019-03-01T07:23:17Z")

</div>

No, jdbc\_validate\_connection as true isnt helping

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<div class="post-metadata">

**Author:** ![ApekshaB](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/apekshab/32/63273_2.png) [@ApekshaB](https://discuss.elastic.co/u/ApekshaB)\
**Post date:** [March 1, 2019, 10:44am UTC](https://discuss.elastic.co/t/commysqljdbcexceptionsjdbc4-communications-link-failure-if-i-schedule-query-every-system-hour/170330/4 "2019-03-01T10:44:15Z")

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doesn JDBCdriver maintain continous connectivity with the database or does it make connection as per the scheduler time( i mean when it needs to run the query).

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<div class="post-metadata">

**Author:** ![ApekshaB](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/apekshab/32/63273_2.png) [@ApekshaB](https://discuss.elastic.co/u/ApekshaB)\
**Post date:** [March 6, 2019, 2:49pm UTC](https://discuss.elastic.co/t/commysqljdbcexceptionsjdbc4-communications-link-failure-if-i-schedule-query-every-system-hour/170330/5 "2019-03-06T14:49:24Z")

</div>

Kindly help me in this regards.  
stuck with the same.

By using autoconnect option as true,  
jdbc\_connection\_string =\> "jdbc:mysql://172.23.125.52:3304/faredge?autoReconnect=true", i am sometimes getting updated rows and new rows, but no fixed pattern.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [April 3, 2019, 2:55pm UTC](https://discuss.elastic.co/t/commysqljdbcexceptionsjdbc4-communications-link-failure-if-i-schedule-query-every-system-hour/170330/6 "2019-04-03T14:55:16Z")

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